HK1215695A1 - Thin film deposition method and deposition device - Google Patents

Abstract

Provided is a method for low-cost deposition of a durable thin film. This deposition device (1) includes a vacuum chamber (11) in which a substrate (100) is arranged at the bottom, a vacuum pump (15) which evacuates the chamber (11), a storage container (23) which is provided outside of the chamber (11) and which stores a film deposition solution (21), a nozzle (17) which at one end has a discharge unit (19) which can discharge the film deposition solution (21), and a pressurizing means (a gas supply source (29), etc.) which pressurizes the liquid surface of the film deposition solution (21) stored in the storage container (23). As the film deposition solution (21), a solution is used which is made up of two or more materials, including a first material (S1) and a second material (S2) having a vapor pressure (P2) higher than the vapor pressure (P1) of the first material (S1), with the concentration of the first material being 0.01 wt% or greater. The film deposition solution (21) is discharged onto the substrate with a discharge pressure of 0.05-0.3MPa in an environment at a pressure of P2 or greater (but not a pressure more than one order of magnitude higher than P2).

Description

Method and apparatus for forming thin film

Technical Field

The present invention relates to a film forming method and apparatus capable of forming a thin film in vacuum. The thin film includes, for example, an organic film, an inorganic film, and the like.

Background

As a film formation method for forming a thin film, for example, an organic film or an inorganic film on a surface of a substrate, a wet method such as a coating method or a dipping method is used. For example, patent document 1 proposes a film forming method in which a notch (scratch) having a depth of 10 to 400nm is formed on a surface of a substrate such as glass or plastic in the air to have a striped fine uneven surface, and then a coating liquid (diluted solution) having a predetermined composition is applied and dried to form an antifouling film (organic film) having a predetermined composition on the fine uneven surface. Patent document 2 proposes a film forming method in which titanium oxide particles are mixed in water to form a suspension, the pH is further adjusted to a specific value, and the suspension is applied to a support and dried to form an inorganic titanium oxide film (inorganic film).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 9-309745

Patent document 2: japanese laid-open patent publication No. 6-293519

Disclosure of Invention

Problems to be solved by the invention

The coating liquid or suspension used in the wet method is a dilute solution having a low solute concentration. Therefore, the density of the film obtained after the heat drying is low, and the function of the formed film is likely to be lost. For example, in a stain-proofing film coated by a wet method, the film formed on the outermost surface is easily scraped off by wiping, and the oil repellency may be lost.

On the other hand, a film formation method of forming a thin film on a substrate by using a vacuum deposition method (dry method) is also conceivable, and in the case of using this method, high vacuum conditions need to be formed during film formation, and an expensive vacuum exhaust system is required. As a result, it is difficult to realize film formation at low cost.

According to one aspect of the present invention, a film forming method and apparatus capable of forming a thin film having durability at low cost can be provided.

Means for solving the problems

In the present invention, "discharge" means that the liquid is directly discharged in a liquid state. "discharging" also includes "spraying" to disperse the liquid. In the "discharge", the physical state and the chemical state of the raw material in the liquid do not change before and after the discharge. Therefore, the principle of "discharge" is different from the principle of vapor deposition in which the physical state of a raw material is changed from liquid or solid to gas, and the principle of CVD in which the chemical state of a raw material is changed.

The present inventors have found that a film having durability can be formed in an atmosphere of a specific pressure (Pc) (a pressure of P2 or higher (excluding a pressure of one order or more higher than P2)) and at a predetermined discharge pressure when discharging a solution composed of 2 or more materials including a 1 st material (S1) and a 2 nd material (S2) having a vapor pressure (P2) higher than the vapor pressure (P1) of S1, and the concentration of the 1 st material (hereinafter also referred to as "S1 concentration") is adjusted. Further, it has been found that since the specific pressure Pc for discharging the solution is mostly in the medium vacuum or low vacuum region, a thin film having durability can be formed at low cost as compared with a vapor deposition method in which a high vacuum condition is required at the time of film formation, and the present invention has been completed.

According to aspect 1 of the present invention (claim 1), there is provided a thin film forming method including the following configuration. The film formation method presupposes formation of a thin film on a substrate in vacuum. The solution contains 2 or more kinds of materials (e.g., the 1 st material (S1), the 2 nd material (S2), the 3 rd material (S3), …, and the like, and is characterized in that the solution is discharged onto the substrate in an atmosphere of a pressure (Pc) set based on the vapor pressure of each material constituting the solution (e.g., S1, S2, S3, …, and the like, the like), for example, P1, P2, P3, …, and the like, the like).

According to the invention of claim 2 (claim 2), there is provided a thin film forming apparatus including the thin film having the following configuration. The film forming apparatus is premised on forming a thin film on a substrate in vacuum, and includes a vacuum container in which a substrate to be formed is disposed, an exhaust unit that exhausts the vacuum container, a storage container that stores a solution containing 2 or more materials, and a nozzle that discharges the solution onto the substrate disposed in the vacuum container. Characterized in that the device is configured to: when the pressure in the vacuum container reaches a pressure (Pc) set based on the vapor pressure of each material constituting the solution, the solution is discharged from the nozzle onto the substrate.

In addition to the above, in the present invention (inventions 1 and 2), as the solution to be discharged onto the substrate, a solution including the 1 st material (S1) and the 2 nd material (S2) having a vapor pressure (P2) higher than the vapor pressure (P1) of S1 as each material constituting the solution, and the concentration of S1 is adjusted to a predetermined value (0.01 wt%) or more is used. The method is characterized in that when the atmosphere pressure (Pc) is P2 or more (excluding a pressure higher by one order of magnitude than P2), the solution is discharged onto the substrate at a discharge pressure within a predetermined range (0.05 to 0.3 MPa).

In the invention 2, the substrate to be subjected to film formation may be disposed below the inside of the vacuum chamber (i.e., vertically below) or on the side of the inside of the vacuum chamber (i.e., horizontally on the side). When the substrate is disposed at the tip (discharge portion) of the nozzle below the inside of the vacuum chamber, the substrate may be disposed so that the solution can be discharged downward (vertically or obliquely) (hereinafter, also referred to as "the discharge direction of the solution downward"), and when the substrate is disposed on the side of the inside of the vacuum chamber, the substrate may be disposed so that the solution can be discharged in the lateral direction (horizontally or obliquely) (hereinafter, also referred to as "the discharge direction of the solution in the lateral direction"). That is, in the invention 2, the position where the discharge portion is provided is not limited.

In the same manner as in the invention 1, the solution may be discharged in either a downward or lateral direction.

In the invention 2, an automation (inline) system including a conveying mechanism for conveying a substrate may be used. In the invention 1, if the film formation is performed in an automated manner with a conveying mechanism, productivity is improved, which is advantageous.

Effects of the invention

According to the invention 1, a solution, which is composed of 2 or more materials including S1 and S2 (where the relationship between P1 of S1 and P2 of S2 is P1 < P2), and whose concentration of S1 is adjusted, is discharged onto a film formation object (substrate) at a discharge pressure within a predetermined range when the atmospheric pressure Pc is P2 or more (where a pressure higher by one order of magnitude or more than P2 is not included). When the solution was discharged under the pressure Pc, S2 volatilized on the substrate, but S1 did not volatilize. Therefore, the thin film formed on the substrate has a high density. That is, according to the invention 1, a thin film having durability can be formed at low cost.

According to the invention 2, it is constituted such that: a solution, which is composed of 2 or more kinds of materials including S1 and S2 (wherein the relationship between P1 of S1 and P2 of S2 is P1 < P2), and whose S1 concentration is adjusted, is discharged from a nozzle onto a film-forming object (substrate) at a discharge pressure within a predetermined range when the atmospheric pressure is P2 or more (wherein a pressure higher by one order of magnitude or more than P2 is not included). When the pressure in the vacuum vessel is Pc, S2 volatilizes even when the solution is discharged, but S1 does not volatilize. Therefore, the thin film formed on the substrate has a high density. That is, according to the invention 2, a thin film having durability can be formed at low cost.

Drawings

FIG. 1 is a schematic sectional view showing an example of a film forming apparatus capable of carrying out the method of the present invention.

(symbol description)

1 … film forming apparatus, 11 … vacuum vessel, 13 … piping, 15 … vacuum pump (exhaust unit), 16 … controller, 17 … nozzle, 18 … pressure detection unit, 19 … exhaust unit, 21 … film forming agent solution, 23 … storage vessel, 25 … infusion tube, 26 … valve, 27 … piping, 29 … gas supply source, 31 … substrate holder, 33 … roller (conveying mechanism), 100 … substrate.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

< example of construction of film Forming apparatus

First, an example of the film forming apparatus of the present invention (the apparatus of the present invention) (in the case where the discharge direction of the solution is downward) will be described.

As shown in fig. 1, a film deposition apparatus 1 as an example of the apparatus of the present invention includes a vacuum chamber 11 in which a substrate 100 to be deposited is disposed. In this example, the vacuum chamber 11 is formed as a hollow body having a substantially rectangular parallelepiped shape, but the present invention is not limited to this shape.

An exhaust port (not shown) for exhausting air is provided near the lower end of the side wall of the vacuum chamber 11. One end of the pipe 13 is connected to the exhaust port, and a vacuum pump 15 (exhaust means) is connected to the other end of the pipe 13. The vacuum pump 15 may be a pump capable of producing a vacuum state of about atmospheric pressure to a medium vacuum (0.1Pa to 100Pa) in this example, and may be, for example, a rotary pump (oil rotary vacuum pump). Although a Turbo Molecular Pump (TMP), an oil diffusion pump, or the like can make a vacuum state of high vacuum (less than 0.1Pa), it is not necessary to use a pump that introduces high cost. Therefore, the apparatus cost can be made inexpensive in this example.

The vacuum pump 15 is operated in response to a command from a controller 16 (control means), and the degree of vacuum (pressure) in the container 11 is reduced through the pipe 13. The vacuum vessel 11 is provided with a pressure detecting unit 18 (a pressure gauge or the like) that detects the pressure inside the vessel 11. The information on the pressure in the container 11 detected by the pressure detecting means 18 is sequentially output to the controller 16. When the controller 16 determines that the pressure in the container 11 has reached a predetermined value, an operation command is sent to the gas supply source 29 (see below).

For example, the pressure in the container 11 can be controlled by introducing a gas such as argon gas into the container 11 through a flow rate adjusting unit (not shown) such as a mass flow controller (MassFlowController) under the monitoring of a pressure control unit (not shown) such as an Automatic Pressure Controller (APC). Further, a valve (not shown) may be provided in a pipe line connecting the exhaust port of the container 11 and the pipe 13 of the pump 15, and the pressure in the container 11 may be controlled by adjusting the opening degree of the valve in a state where the pump 15 is operated.

In this example, an openable/closable door (not shown) serving as an isolation means may be provided below the side wall of the vacuum chamber 11, and a load lock chamber (not shown) may be connected to the openable/closable door.

In this example, one end of the nozzle 17 is inserted downward into the vacuum chamber 11, and the other end of the nozzle 17 is exposed to the outside of the chamber 11. One end of the nozzle 17 present inside the container 11 is connected to the discharge portion 19. The number (number) of nozzles 17 inserted into the container 11 is not limited. Depending on the size of the container 11, two or more nozzles 17 may be used in a single container 11. In this example, when the extending direction of the nozzle 17 is set as the central axis, the discharge portion 19 may be configured to spray the film-forming agent solution 21 in a full cone or fan shape at an angle θ of, for example, 30 degrees to 80 degrees. The discharge section 19 discharges solution-like particles having a size of, for example, several hundred μm.

The other end of the nozzle 17 exposed to the outside of the container 11 is connected to the other end of the infusion tube 25, and one end of the infusion tube 25 is inserted into the storage container 23 for hermetically storing the film-forming agent solution 21. Thus, it is constituted as follows: when the valve 26 is opened, the film-forming agent solution 21 is delivered from the storage container 23 through the delivery tube 25, and is discharged downward into the container 11 from the discharge portion 19 connected to one end of the nozzle 17.

In this example, one end of a gas supply pipe 27 for pressurizing the liquid surface in the container 23 is connected to the storage container 23, and the other end thereof is connected to a gas supply source 29.

The gas supply source 29 operates in response to a command from the controller 16 to supply gas into the pipe 27 to pressurize the liquid surface of the storage container 23. Thus, in this example, the liquid surface of the storage container 23 is pressurized, and the film-forming agent solution 21 is pressure-fed into the infusion tube 25. The present invention is not limited to the mode of discharging the solution 21 by such pressurization.

A substrate holder 31 for holding a substrate 100 to be film-formed is disposed below the inside of the vacuum chamber 11. In this example, the substrate holder 31 is supported by a conveyance mechanism constituted by two or more rollers 33, 33, …, etc., and the substrate holder 31 is movable within the container 11 by the operation of the conveyance mechanism. Note that the movement here includes rotation in addition to the linear movement (in this example). In the case of rotation, the substrate holder 31 may be configured as a turntable, for example. The inner surface of the substrate holder 31 has a concave substrate holding surface, and the substrate 100 (one or two or more) is held by bringing the back surfaces of the substrates 100 to be film-formed into contact with each other at the time of film formation.

In the present invention, the distance D between the discharge part 19 and the substrate 100 is not particularly limited as long as the film-forming agent solution 21 discharged in a liquid state from the discharge part 19 can reach the substrate 100 in a liquid form. This is because the distance that the film-forming agent solution 21 can reach the substrate 100 from the discharge portion 19 varies depending on various factors such as the orientation of the discharge portion 19, the initial velocity of the film-forming agent solution 21 when discharged from the discharge portion 19, and the vapor pressure (P2) of the 2 nd material (s 2. described later) contained in the film-forming agent solution 21 at room temperature.

In the present example in which the film-forming agent solution 21 is discharged downward, the distance D is adjusted to be about 300mm or less by adjusting the arrangement of the discharge portion 19 and the substrate holder 31, so that the film obtained can easily have sufficient film strength and the durability level can be easily improved.

In the present example in which the film-forming agent solution 21 is discharged downward, by disposing the discharge portion 19 so that the distance D from the substrate 100 is 150mm or more, a sufficient effective discharge area of the film-forming agent solution 21 can be secured, which is advantageous in suppressing wasteful consumption of the film-forming agent solution 21, and as a result, is more advantageous in reducing the cost of film formation.

In the case of this example in which the film-forming agent solution 21 is discharged downward, if the distance D is too long, the thinner (solvent) of the film-forming agent solution 21 volatilizes during the discharge process, and leveling after reaching the substrate becomes difficult to occur, so that the film distribution becomes uneven, and the film performance may be degraded. When the distance D is too short, the effective discharge region is narrowed, and therefore, the film-forming agent solution 21 is unnecessarily consumed, and film spots may occur.

The controller 16 has a container internal pressure control function, and operates the vacuum pump 15 and the pressure detection unit 18 to adjust the degree of vacuum (i.e., the film formation start pressure) in the container 11 to an appropriate level. At the same time, it also has a liquid surface pressurization pressure control function for adjusting the pressure applied by the gas supplied from the gas supply source 29 to the liquid surface in the storage container 23. The controller 16 also has a function of controlling the operation and stop of the conveying mechanism including two or more rollers 33 and the like.

< example of film formation >

Next, an example of the film forming method of the present invention (the method of the present invention) using the film forming apparatus 1 will be described.

(1) First, a film-forming agent solution 21 is prepared. In this example, a case where the film-forming agent solution 21 is composed of a solution of 2 materials including the 1 st material (S1) and the 2 nd material (S2) will be described as an example, and in the following description, the component of the film-forming material (raw material for forming a thin film) will be S1 and the component (liquid) for dissolving S1 will be S2 by comparing S1 with S2.

S1 includes a liquid in addition to a solid such as a powder.

In the case where the solution 21 is a mixed system of a liquid (for example, the liquid a) and a liquid (for example, the liquid B), the liquid a constitutes S1 as long as the liquid a is a component of a film-forming material (a constituent material of a thin film) even if the concentration (amount or ratio) of the liquid a in the solution 21 is higher than the concentration of the liquid B (specifically, even if the concentration of the liquid a is high, exceeding 50 wt%). That is, the concentration in the solution itself does not determine the difference between S1 and S2.

Examples of the thin film include an organic film and an inorganic film. In addition, an organic-inorganic hybrid film formed of a material having both an organic component and an inorganic component is also included. Examples of such a thin film include an antifouling film, a waterproof film, a moisture-proof film, an organic EL film, and a titanium oxide film, and examples of the raw material of each of these films (corresponding to S1 in this example) include a hydrophobic reactive organic compound (an organic compound having at least one hydrophobic group and at least one reactive group capable of bonding to a hydroxyl group in one molecule), a waterproof material, a moisture-proof material, an organic EL material, and titanium oxide.

Examples of the hydrophobic reactive organic compound that can be used as a material for forming an antifouling film, which is an example of an organic-inorganic hybrid film, include an organic silicon compound containing a polyfluoroether group or a polyfluoroalkyl group. As examples OF products, OF-SR (oil repellent) and OF-110 (water repellent) from Canon Optron are available.

Among the hydrophobic reactive organic compounds, a substance having a low vapor pressure (P1) at room temperature, for example, 10^-4Pa front and back (preferably 0.8 × 10)^-5Pa～3×10^-4Degree of Pa, more preferably 10^-4Pa or less) (liquid at room temperature).

S2 that can be used is not particularly limited as long as it is a component S1 that can dissolve the constituent materials of the various films. When a hydrophobic reactive organic compound containing fluorine is used as S1, a solvent (fluorine-based solvent) containing fluorine can be used as S2 to improve affinity.

Examples of the fluorine-based solvent include a fluorine-modified aliphatic hydrocarbon-based solvent (e.g., perfluoroheptane, perfluorooctane, etc.), a fluorine-modified aromatic hydrocarbon-based solvent (e.g., hexafluorometaxylene, trifluorotoluene, etc.), a fluorine-modified ether-based solvent (e.g., methyl perfluorobutyl ether, perfluoro (2-butyltetrahydrofuran), etc.), a fluorine-modified alkylamine-based solvent (e.g., perfluorotributylamine, perfluorotripentylamine, etc.), and the like.

Among the above-mentioned fluorine-based solvents, a substance having a very high vapor pressure (P2) at room temperature, for example, 10, can be selected³Pa or more (preferably 0.8 × 10³Pa or more and less than atmospheric pressure (1.01325 × 10)⁵Pa), more preferably 6.0 × 10³Pa～1.6×10⁴Pa degree), and excellent volatility at ordinary temperature.

The fluorine-containing solvent may be used alone or in combination of 2 or more. When 2 or more kinds are mixed for use, the whole mixture may be selected so as to have the above vapor pressure range.

In the present invention, in the case where the concentration of the film forming agent solution 21 to be used (S1 concentration) is required to be 0.01 wt% or more and the concentration of S1 is too low, the film forming start pressure (hereinafter, the same shall apply) is P2 or more (note that the pressure higher than P2 by one order of magnitude or more is not included), even if the discharge pressure of the liquid is appropriately adjusted, the film forming agent solution 21 may undesirably drip from the discharge portion 19 before the film forming starts, and the film forming may not be appropriately performed. Even if the film can be formed, it is difficult to prevent the film density of the thin film from decreasing.

In the present invention, the concentration of S1 in the film-forming agent solution 21 may be 0.01 wt% or more, and may be preferably 0.03 wt% or more, and more preferably 0.05 wt% or more. When the film-forming agent solution 21 having an S1 concentration of 0.03 wt% or more is used, the durability level of the resulting film is easily improved even if the film formation start pressure is set to P2 or more (not including a pressure one order of magnitude or more higher than P2).

The upper limit of the concentration of S1 may be determined in a range in which so-called fluid clogging is not caused by sticking to the inside of the infusion tube 25 or the discharge part 19, taking into consideration the type of S1 or S2 to be used, the inner diameter and length of the infusion tube 25, the configuration of the discharge part 19, and the like. For example, when a hydrophobic reactive organic compound is used as S1 and a fluorine-based solvent is used as S2, the concentration of S1 is not 100 wt% (that is, S2 is 0 and only S1), and even if the upper limit thereof is close to 100 wt% (in a state of being diluted in a slight amount of S2), film formation can be performed without causing liquid clogging in the infusion tube 25 and the discharge section 19 by devising the film formation starting pressure or the discharge pressure of the liquid, the inner diameter and length of the infusion tube 25, the configuration of the discharge section 19, and the like, and sufficient film performance can be obtained. Therefore, in this example, the upper limit of the concentration of S1 is preferably 70 wt%, more preferably 40 wt%, and still more preferably 10 wt%, as long as it is less than 100 wt%.

Particularly preferably, the content is, for example, 2 wt% or less, preferably 1 wt% or less, and more preferably 0.1 wt% or less. When the concentration of S1 is 2 wt% or less, film spots (deposition of excess material not formed) are less likely to occur on the film formation surface of the film formation target (two or more substrates 100), and unnecessary consumption of the film-forming agent solution 21 is finally suppressed, thereby making it easier to reduce the cost of film formation.

When the concentration of S1 is high, the component S1 may be fixed inside the infusion tube 25 or the discharge part 19 due to the film formation start pressure and the discharge pressure of the liquid, thereby causing so-called liquid clogging.

The viscosity of the film-forming agent solution 21 to be used is not particularly limited, and may be appropriately adjusted to such a degree that the solution 21 smoothly flows in the infusion tube 25, can be appropriately discharged from the discharge unit 19, and does not become fixed in the infusion tube 25 or the discharge unit 19 to cause so-called fluid clogging, in consideration of the inner diameter and length of the infusion tube 25, the configuration of the discharge unit 19, and the like.

(2) The prepared film forming agent solution 21 is then added to a storage container 23. In this example, two or more substrates 100 are held in the concave portion of the substrate holder 31 outside the container 11.

Examples of the substrates 100 that can be fixedly held by the substrate holder 31 include a glass substrate, a metal substrate, and a plastic substrate. Depending on the type of the substrate 100, a film formation without heating (a method of not heating the inside of the container 11 during film formation) may be selected. When film formation is selected without heating, a plastic substrate may be used in addition to a glass substrate or a metal substrate. As each substrate 100, a substrate shaped into a plate, a lens, or the like may be used, for example. The substrate 100 may be wet-cleaned before being fixed to the substrate holder 31, or may be wet-cleaned after being fixed and before the film formation is started.

(3) Next, the substrate holder 31 holding two or more substrates 100 is set inside the container 11 (in the case of batch processing). At this time, the open/close door provided below the side wall of the container 11 (see above) may be opened, and the substrate holder 31 holding the substrate 100 may be moved from the load lock chamber and set in the container 11 by operating the transport mechanism (roller 33). Thereafter, the pump 15 is operated in accordance with a command from the controller 16 to start the evacuation of the vacuum chamber 11.

In the case of continuous processing without making the substrate holder 31 stationary in the container 11 during film formation described later, the substrate holder may be moved in the container 11 at a predetermined transport speed during film formation (automated method). From the viewpoint of productivity, a high conveyance speed is advantageous. However, from the viewpoint of effective utilization of a film-forming agent (a film-forming material of a thin film, corresponding to S1 in this example), film performance, and the like, it is preferably set to a level of, for example, 50 to 90 mm/sec.

The controller 16 sequentially detects the pressure (Pc) in the container 11 based on the output from the pressure detection unit 18. In this example, when it is determined that the pressure Pc in the container 11 is equal to or higher than the vapor pressure (P2) of S2 contained in the film-forming agent solution 21 (P2 ≦ Pc)), the operation can be started by controlling the container internal pressure control function, while maintaining this state. The gas supply source 29 that receives the operation command sends gas into the pipe 27, and the liquid surface of the storage container 23 is pressurized by the gas. The film-forming agent solution 21 is thus fed under pressure through the liquid transport tube 25, introduced into the nozzle 17, and then discharged from the discharge unit 19 into the container 11.

In the present invention, the pressure Pc inside the container 11 from which the film-forming agent solution 21 is discharged may be set to a pressure that is less than or equal to one order of magnitude higher than P2. With such setting, the occurrence of film defects can be effectively prevented.

When the film formation is performed at an excessively high pressure (for example, a pressure higher by one order of magnitude or more than P2) as compared with the vapor pressure P2 of the solvent S2 at room temperature, the solvent remaining in the film formation can be removed by a drying step or the like after the film formation, but the film is not formed in this portion (solute components are not uniformly adhered, and film defects are formed). When the solute component is not uniformly adhered to the substrate 100, a thin film is not formed on the substrate 100, and film separation occurs from the non-existing portion of the film during rubbing, and improvement of durability is not expected.

In the present invention, pressure (discharge pressure) may be applied to the film-forming agent solution 21 when it is discharged from the discharge portion 19. This is because, in the present invention in which the film formation start pressure is P2 or more (not including a pressure higher by one order of magnitude than P2, among others), by applying the discharge pressure, the form of liquid discharge (discharge shape) is the most effective diffusion form (shower shape), and the occurrence of wasteful consumption of liquid is reduced, thereby achieving cost reduction of film formation of a thin film and facilitating improvement of production efficiency. Among them, from the viewpoint of stabilizing the discharge shape, it is preferable to use a spray nozzle, and the film-forming agent solution 21 can be discharged at a discharge pressure (gauge pressure) of 0.05 to 0.3 MPa. By discharging the liquid at the specific discharge pressure, the discharge shape is further stabilized, and the occurrence of wasteful consumption of the liquid is further reduced, whereby the cost for film formation of a thin film is further reduced, and the production efficiency is easily further improved. The film-forming agent solution 21 is discharged under the above-mentioned specific discharge pressure by discharging the gas into the pipe 27 so that the liquid surface of the storage container 23 is pressurized to 0.05 to 0.3 MPa.

The discharge time of the film forming agent solution 21 from the discharge portion 19 is not limited. Because it varies according to the size, number, etc. of the substrates 100. The thickness of the thin film formed on the substrate 100 is not limited, either, because it varies depending on the type of material contained in the film-forming agent solution 21, the discharge time of the solution 21, and the like.

In this example, when the film-forming agent solution 21 is discharged from the discharge unit 19 located at the distance D from the substrate 100, the pressure Pc in the container 11 at the start of the discharge (i.e., film formation) is controlled to be within a predetermined range (P2 ≦ and a pressure more than one order of magnitude higher than P2), the S1 concentration and the discharge pressure of the film-forming agent solution 21 may be adjusted to be within predetermined ranges (S1 concentration: 0.01 wt% or more, discharge pressure: 0.05 to 0.3MP), because if the pressure Pc in the container 11 at the start of the discharge is P2 or more, the film density of the thin film formed on the substrate 100 cannot be prevented from decreasing without adjusting the S1 concentration and the discharge pressure of the film-forming agent solution 21, and good film formation cannot be performed.

The mechanism of the decrease in film density of the thin film is as follows. That is, when the pressure Pc in the container 11 at the start of discharge is equal to or higher than P2, S2 in the film forming agent solution 21 may remain on the substrate 100 without adjusting the S1 concentration and the discharge pressure of the film forming agent solution 21. S2 remaining on the substrate 100 volatilizes during drying in the subsequent step, thereby inducing a release state, and as a result, the film density of the thin film decreases.

In this example, since the film-forming agent solution 21 having the concentration of S1 adjusted to the predetermined range is used and discharged under the predetermined discharge pressure, even if the pressure Pc in the container 11 at the start of discharge is controlled to be equal to or higher than P2, the S2 in the film-forming agent solution 21 does not remain on the substrate 100, and the film-release state can be avoided, and as a result, the film density of the thin film can be prevented from decreasing.

As described above, the thin film formed in this example includes, for example, an antifouling film, a waterproof film, a moisture-proof film, an organic EL film, a titanium oxide film, and the like. The present invention is a film forming method to which all compounds including organic materials, inorganic materials, organic-inorganic hybrid materials, and the like can be applied. Hereinafter, a case where the thin film formed in this example is an antifouling film (an example of an organic-inorganic hybrid film) will be described as an example.

The antifouling film is a film having water repellency and oil repellency, and has a function of preventing adhesion of oil stains. Here, "prevention of adhesion of oil stains" means not only that oil stains do not adhere to the surface but also that even if they adhere to the surface, they can be easily wiped off. Namely, the antifouling film maintains oil repellency. Specifically, the durability level of the antifouling film is maximally improved even when based on 1kg/cm²The loaded steel wool #0000 of (1) is reciprocated more than 2000 times (preferably 4000 times, more preferably 6000 times), and also can wipe off the ink of the oil-based pen.

Such durability improvement is due to: when the film-forming agent solution 21 having the S1 concentration and the discharge pressure adjusted to the predetermined range is discharged from the discharge unit 19 located at the distance D from the substrate 100, the pressure Pc in the container 11 at the start of the discharge is adjusted to the predetermined range (a pressure of P2 ≦ and < one order of magnitude higher than P2), so that the constituent molecules (film molecules) of the S1 component are surely filled on the surface of the substrate 100, and the nonexistent portion of the film does not exist.

As described above, in the film forming method in which the film forming agent solution 21 is discharged in the downward direction using the film forming apparatus 1 of this example, S1 and S2 are mixed, and the film forming agent solution 21 whose S1 concentration is adjusted is used, and discharged onto the substrate 100 at a discharge pressure within a predetermined range (0.05 to 0.3MPa) at a specific pressure Pc which is preferably a pressure of S2, i.e., a pressure of P2 or more (excluding a pressure higher by one order of magnitude than P2). According to the film forming method of this example, after the film-forming agent solution 21 discharged from the discharge portion 19 reaches the substrate 100 in a solution state, the solvent component evaporates, and the film (thin film) is formed and the density is increased. Finally, a thin film having an improved level of durability can be formed on each substrate 100 at low cost.

When the thin film formed by the method of this example is an antifouling film, the antifouling film can be formed even under a heavy load (for example, 1 kg/cm)²Right and left loads) of the stain-proofing film can effectively remain the components of the stain-proofing film even if oil such as fingerprints adhering to the surface is wiped off.

The thin film formed by the method of this example is not limited to the antifouling film. There are also examples of the formation of an inorganic film. In the case of preparing a suspension of 4 g/liter (S1 is titanium oxide particles, S2 is water, and the vapor pressure of water at normal temperature is about 3000Pa) by mixing titanium oxide particles in water, the pressure Pc in the container 11 is set to 3000Pa, and the discharge pressure of the suspension is: when the film was formed by discharging the solution under 0.2MPa, a titanium oxide film having a refractive index of 2.400 with respect to light having a wavelength of 550nm and excellent optical characteristics was formed. It is considered that by using a suspension in which the titanium oxide particle concentration is adjusted to a predetermined range and discharging the suspension at a discharge pressure of 0.2MPa when the container internal pressure Pc is 3000Pa, a dense inorganic titanium oxide film can be formed and good optical properties can be obtained.

< other embodiments >

The film forming apparatus of the present invention is not limited to the above-described mode of the film forming apparatus 1 (the discharge direction of the film forming agent solution 21 is downward), and the nozzle 17 may be disposed in a lateral direction (the discharge direction of the film forming agent solution 21 is lateral). In the case of the lateral direction, for example, one end of the nozzle 17 may be inserted in the horizontal direction from the inner side of the vacuum chamber 11, and the other end of the nozzle 17 may be exposed to the outside of the side wall of the chamber 11. Alternatively, a rotating member (not shown) which can rotate by, for example, ± 90 degrees may be attached to the nozzle 17 at a portion (including the discharge portion 19) near the middle in the longitudinal direction thereof, and then one end of the nozzle 17 (to which the discharge portion 19 is connected) may be inserted downward from the inside of the vacuum chamber 11, and the other end of the nozzle 17 may be exposed to the outside of the chamber 11. In any case, when the nozzle 17 is provided in a lateral direction, the substrate holder 31 is disposed on the inner side of the vacuum chamber 11 so that the surface holding the substrate 100 faces the discharge portion 19 connected to one end of the nozzle 17.

The substrate holder 31 may be movable, and the nozzle 17 may be movable by a carrier not shown. Alternatively, the nozzle 17 may be separately movable by a conveyance mechanism not shown. In this case, the film forming method can be applied even if the nozzle 17 side is moved.

Examples

Next, the present invention will be described in further detail by taking examples in which the embodiments of the present invention described above are further embodied.

[ Experimental examples 1 to 6]

< 1. preparation of antifouling film sample >

Using the film formation apparatus 1 shown in FIG. 1, 2 substrates 100 (glass substrates, size: 50 mm. times.100 mm) were set on the substrate holding surface of the substrate holder 31.

Film-forming agent solutions a to e having the compositions described in table 1 were prepared.

[ Table 1]

In table 1, "oil repellent 1" is a surface antifouling coating agent (product name: OptoolDSX, component name: fluorine-containing organosilicon compound, manufactured by dajinian industries), "oil repellent 2" is a fluorine-based antifouling coating agent (product name: KV-178, component name: fluorine-containing organosilicon compound, manufactured by shin-Etsu chemical industries), "solvent 1" is a fluorine-based solvent (product name: Novec7200, manufactured by sumitomo 3M), and "solvent 2" is a fluorine-based solvent (product name: Novec7300, manufactured by sumitomo 3M).

Other film forming conditions such as the pressure Pc and the distance D in the container 11 at the start of film formation are shown in table 2. A spray nozzle capable of discharging 140 to 260 μm-sized solution-like particles was used as a nozzle discharge part, and the film-forming agent solution discharge time was uniformly set to 30 seconds. Then, samples of each experimental example were obtained in which an antifouling film having a thickness of 10 to 15nm was formed on the substrate 100.

In experimental examples 1 to 3, the anti-fouling film was formed in a state in which the substrate holder 31 on which the substrate 100 was mounted was stationary in the vacuum chamber 11 (batch processing). In experimental examples 4 to 6, film formation (continuous processing) was performed while conveying the substrate holder 31 on which the substrate 100 was set in the vacuum chamber 11.

< 2. evaluation >

2-1. durability of antifouling film

The antifouling film of each of the obtained samples of the experimental examples was supported by 1cm on the surface thereof²Steel Wool (SW) #0000 to apply 1kg/cm²The load of (2) was reciprocated (rubbed) on a 50mm straight line at a speed of 1 second for 1 reciprocation. After 3500 times of the reciprocation, the contact angle of pure water on the antifouling film surface was measured. The contact angle of pure water on the antifouling film surface immediately after the film formation was measured. The contact angle value was an average value of the contact angle values measured after dropping pure water for 1 minute, which was obtained by repeating dropping and measurement 5 times. The results are shown in Table 2.

2-2 maximum number of cycles of scratching of antifouling film

The antifouling film of each of the obtained samples of the experimental examples was supported by 1cm on the surface thereof²Steel Wool (SW) #0000 to apply 1kg/cm²The load of (2) was reciprocated (rubbed) on a 50mm straight line at a speed of 1 second for 1 reciprocation. Each 100 times of this reciprocating operation, a test surface (antifouling film surface) was marked with a line using an oil-based universal pen (organic solvent-based marker, trade name: Mckee ultra thin, manufactured by Zebra Co., Ltd.), and whether or not the test surface could be wiped off with a dry cloth was evaluatedAn organic solvent type ink for an oil-based all-purpose pen. As a result, the maximum number of rubbing cycles that the organic solvent-based ink can be wiped off is shown in table 2.

[ Table 2]

<3 > examination

3-1 cases of batch treatment (Experimental examples 1 to 3b)

As shown in tables 1 and 2, in experimental examples 1 and 2 (discharge under low vacuum), the concentration of S1 and the discharge pressure of the film forming agent solution and the pressure Pc at the time of discharging the film forming agent solution were appropriately adjusted, and the contact angle of the antifouling film surface immediately after film formation was hardly decreased after SW rubbing, and the durability was extremely excellent. The maximum number of rubbing cycles was 3500 or more, which was sufficient, and it was confirmed that the rubber had a rubbing resistance which could be practically used.

On the other hand, in the case of experimental example 3 (spraying under atmospheric pressure) in which Pc is too high than P2 and experimental example 3a in which Pc is higher than P2 by one order or more, the contact angle of the antifouling film surface immediately after film formation is greatly reduced after SW rubbing. Further, the maximum number of repeated scratches was also extremely small, and it was confirmed that the durability was not sufficient.

Pc is within an appropriate range, but when the discharge pressure of the film-forming agent solution is too low (experimental example 3b), a sufficient contact angle cannot be obtained on the surface of the antifouling film immediately after film formation. Further, the maximum number of repeated scratches was also extremely small, and it was confirmed that the durability was not sufficient.

3-2 cases of continuous treatment (Experimental examples 4 to 6)

When the substrate conveyance speed was increased, the durability of the antifouling film was decreased, and the maximum number of repeated scratches tended to decrease. Experimental example 5 is excellent in balance between film properties and productivity.

Claims (4)

1. A film forming method for forming a thin film on a substrate in vacuum, characterized in that a solution containing a 1 st material (S1) and a 2 nd material (S2) having a vapor pressure (P2) higher than the vapor pressure (P1) of S1 and containing 2 or more materials and having a concentration of the 1 st material of 0.01 wt% or more is discharged onto the substrate at a discharge pressure of 0.05MPa to 0.3MPa in an atmosphere of a pressure of P2 or more, wherein the pressure of P2 or more does not include a pressure of one order of magnitude or more higher than P2.

2. The film forming method according to claim 1, wherein the film forming is performed in an automated manner with a conveying mechanism.

3. A film forming apparatus for forming a thin film on a substrate in vacuum, the apparatus comprising:

a vacuum chamber in which a substrate to be film-formed is disposed;

an exhaust unit for exhausting the vacuum container;

a storage container that stores a solution composed of 2 or more materials, the 2 or more materials including a 1 st material (S1) and a 2 nd material (S2) having a vapor pressure (P2) higher than the vapor pressure (P1) of S1, and the concentration of the 1 st material in the solution being 0.01 wt% or more;

a nozzle for discharging the solution onto the substrate; and

a pressurizing unit for pressurizing the liquid surface stored in the storage container;

it is constituted as follows: and (c) when the pressure in the vacuum container reaches a pressure of P2 or more, discharging the solution from the nozzle onto the substrate by pressurizing the liquid surface in the storage container to 0.05MPa to 0.3MPa, wherein the pressure of P2 or more does not include a pressure of one order of magnitude higher than P2.

4. The film forming apparatus according to claim 3, wherein the apparatus is an automated system including a conveying mechanism for conveying the substrate.